The first thing I would try is the old cartridge, if you still have it - did the fault start immediately on fitting the new cartridge?  If so, and you don't have the old one, simply remove the cartridge, check the contacts are clean and refit. Then try another amplifier, just to rule that out (or try another line input on the same amplifier). There could be a break in the cable inside the DIN plug.  Either try moving the cable around where it enters the plug, or it may be possible to prise the plug open (sliding the plastic cover away from the pins) and see if there is a loose connection inside. If none of the above finds the problem, the fault is probably within the BG6500 or the cartridge, hence specialist knowledge may be required to investigate. (PS:  I'll delete your previous thread/post - just reply within this thread once you have an update or require further advice)

I addition to Guy’s excellent tips, if you have a multimeter you can measure the resistance  between the top and bottom pins of each side of the cartridge. The readings should be a within 2% of each.

Look at the muting relay. It may have corroded.

In Beogram 6500 muting is not done by a relay but by a mechanically operated switch. This switch does not break the signal paths, - it grounds them. This means, that a bad contact won't cause silence but instead the muting will fail and sound will be audible when the needle lands on the record and lifts again. If you are sure, your amplifier is good, I agree on: - Cartridge - DIN solders - Broken tonearm wiring inside carriage housing - Bad RIAA connection inside the Beogram - Faulty RIAA in that order. Martin

It's been a few months. I brought it in to an electronics shop that has worked on B and O stuff before. After a few weeks, they couldn't figure out the problem. I have Beogram 5500 as well that I screwed up trying to fix the string that broke. After fixing it, the tone arm assembly fell apart. This. is out of my wheelhouse. I'm in NYC. Does anyone know of any repair people in the area?